Happy twirthday, Twitter!

After five years, people still don’t know what Twitter is for – and that is what makes it great.

One of the loveliest things about Twitter is that the question "What is Twitter for?" still hasn't been satisfactorily answered. No one knows what it's for. We all have our own idea, and we all have our own ways of using it – but none of us has the definitive answer. I can't sit here and say, "Well, the way that we should use Twitter is X," because you may well shake your head and disagree vehemently. Write a passive-aggressive tweet saying "Oh, here goes some other blogger talking about Twitter, thinking they know it all" if you like. We're all as clueless as everyone else who's chirping away, which is as it should be.

Some people have tried to write "How to" guides, or the dos and don'ts of Twitter. Even the entertaining ones are entirely wrong – complete and utter nonsense. The etiquette isn't defined, because there is no etiquette and there is no protocol, which can irk some people who like to have a set of instructions before they embark on anything. But there is no road map and there are no instructions: you just rabbit away and listen to other people rabbiting away, and you either like or don't like what you hear, or say. That's about it.

I find the lack of rules refreshing. There's a lack of stuffiness about it, which is a delight. Should you swear, or should you try to be nice to people? Should you have arguments, or should you try to discuss things in a grown-up way? Should you be upset if someone annoys you, and should you unfollow or just block them? What's the right thing to do? I have no idea. And I love the fact that I have no idea.

For some, Twitter is a threatening place, a sea of anonymity, a soup of avatars bubbling away with thinly disguised smug superiority, a vast army of slightly shouty liberals whipped up into a frenzy, an angry mob of mumbling rage with flaming torches forever at the ready, waiting to be called into action at a click of Stephen Fry's fingers. But it's not really like that, I don't think. You can accuse Twitter of having a liberal bias, if you like – or say it reflects the liberal bias of human beings – but it's not a place to be afraid of, whatever your view. You can seek out the people you like, and ignore the ones you don't.

That said, it's not necessarily an echo chamber, either. You can follow as many of your enemies as you want, just to keep tabs on them if you like.

The triviality and banality delight me, too. A veritable squadron of dusty, corduroy-clad newspaper columnists have scoffed at Twitter as "just writing about what you had for lunch", but I find that kind of thing rather dismissive. Not everything in life is profound, nor needs to be. "I am on a bus," the beautifully mundane refrain of @themanwhofell, for example, is perfect percussion for the whimsy in his other tweets. You can read something astonishingly sparkling one moment, then something spectacularly tedious the next. But then these are real people, without narrative arcs; these are just the random thoughts of anyone, anywhere.

For me, Twitter has been a joy so far. It might drift off and die a MySpace-style death one day; it might become even more popular. But it's made me laugh out loud, cry to myself and come across some brilliant writing that I wouldn't otherwise have seen. Every day can bring surprises, or just more of the same. So there is only one rule: keep it under 140 characters (which I have signally failed to do here). Apart from that, do what you like.